PDF(Pubmed)
Abstract：
Ecosystem engineers alter their environment often benefiting their own survival and growth yielding self-reinforcing feedbacks. Moreover, these habitat modifications have been found to facilitate recruitment of conspecifics for some species, while for others engineering inhibits recruitment. Whether dune grasses facilitate or inhibit recruitment of conspecifics is yet unknown. Here, we investigated how habitat modification by European marram grass (Ammophila arenaria) through embryonic dune development affects recruitment from seeds and marine dispersed rhizome fragments. Specifically, we tested at three locations with different dune morphologies how habitat modification affected natural seed and rhizome presence and shoot emergence from plots in which seeds or rhizome fragments were added. In addition, we investigated how sediment burial (i.e., the main effect of habitat modification by dune grasses) affected germination and emergence in a controlled experiment. Results show that regardless of habitat modification or beach width, seeds and rhizomes were absent in natural conditions. Habitat modification negatively affected shoot emergence from seeds (8 × less) and rhizomes (4 × less) and was negatively related to sediment dynamics. Furthermore, fewer seedlings were found with higher elevations. In controlled laboratory conditions, the highest seedling emergence was found with slight burial (0.5-3 cm); both germination and seedling emergence decreased as seeds were buried deeper or shallower. Overall, habitat modification by marram grass negatively affects recruitment of conspecifics through increased sediment dynamics and elevation. Consequently, storm events or eradication programs that include removal of adult vegetation-which leads to an unmodified system-might benefit new recruitment from seeds or clonal fragments.
摘要：
生态系统工程师改变他们的环境，往往有利于他们自己的生存和成长，产生自我强化的反馈。此外，已发现这些栖息地的修改有助于某些物种的物种招募，而对其他人来说，工程抑制了招聘。沙丘草是否促进或抑制特定物种的募集尚不清楚。这里,我们调查了欧洲marram草（Ammmophilaarenaria）通过胚胎沙丘发育对栖息地的改变如何影响种子和海洋分散的根茎碎片的募集。具体来说,我们在三个具有不同沙丘形态的位置测试了栖息地的改变如何影响天然种子和根茎的存在以及添加了种子或根茎片段的地块的芽出苗。此外,我们调查了沉积物如何埋藏(即，沙丘草改变栖息地的主要影响）在受控实验中影响了发芽和出苗。结果表明，无论栖息地的修改或海滩宽度，在自然条件下没有种子和根茎。生境修饰对种子（8倍以下）和根茎（4倍以下）的芽出苗产生负面影响，并且与沉积物动力学呈负相关。此外，发现较高海拔的幼苗较少。在受控的实验室条件下，发现出苗最高的是轻度埋葬（0.5-3厘米）；随着种子埋深或浅，发芽和幼苗出苗均减少。总的来说,通过增加沉积物动力学和海拔，marram草的栖息地改变会对物种的募集产生负面影响。因此,风暴事件或根除计划，包括移除成年植被-这导致了一个未修改的系统-可能会受益于种子或克隆碎片的新招募。
